Furnace for the pyrolytic treatment of hydrocarbon oils



July 21, 1936. c. OFMELBERG FURNACE FOR THE PYROLYTIC TREATMENT OFHYDROCARBON OILS Filed June 25, .1934 2 Sheets-Sheet l INVENTOR Car/ 0.Me/erg BY .15: 4 am ATTORNEY y 21, c. o. MELBERG 2,048,351

I FURNAQE FOR THE PYROLYTIC TREATMENT OF HYDROCARBON OILS Filed June 23,1954 2 Sheets-Sheet 2 ATTORNEY INVENTOR Gar/ 0. Ms/berg O O. O'OOGOOOOQOO.

Patented July 21, 1936v i i i FURNACE FOR THE PYROLYTIC TREAT- MENT FHYDROCARBON OILS Carl 0. Melberg, Ponca 'City, Okla., as signor toContinental Oil Company, Ponca City, Okla., a corporation of DelawareApplication June g3, 1934, Serial No. 732,051

, I'Claim. (Cl. 196-116) My invention relates to a furnace for theconstructed and positioned that the tubes may pyrolytic treatment ofhydrocarbon oils, and .be removed, cleaned, inspected, and/or replacedmore particularly to a novel furnace constructhrough the headers byremoving header covers. tion adapted to be used for cracking, heating,The furnace is fired at any suitable point and is and/or viscositybreaking of hydrocarbon oils. provided with a furnace gas duct arrangedwith 5 Theuse of pipe furnaces in which oil is flowed its axiscoincident with the axis of the setting through a conduit or coil ofcomparatively small in order to provide for a straight line flow incross sectional area externally heated by either the radiant heatsection, preve t turbulenceradiant or convection heat has lately becomeIn the u t y be p s t ned-convection tube prevalent in the pyrolytictreatment of hydrob s- The O l to be P ocessed may be char d 10 carbonoiIs, The processing and pyrolytic t0 the convection tube bank andthenthrough treatment ofhydrocarbon oils require comparaa the radiant tubebank. It may be charged to a tively high temperatures very much inexcess section of the convection tube bank, then to the of those used inheating water to form steam. radiantly heated bank and then to anothersec-.

The hydrocarbon oil is of such characterv tion'of the convection heatbank. The provision that, if heated to certain temperatures, it"tends smade, if d sir d. f r p v t n th ver eat to decompose to form lowerboiling hydrocarbons ing o t e 011 being P o sed by injecting a and thisdecomposition is attended by deposition que ch 0 at a suitab e place inthe heating coil. of carbon and tarry substances. Frequently, the In thea mpanying drawings which form part zo gases and lower boilinghydrocarbons which may of the instant Specification a d a e to be readin be formed by the pyrolytic treatment of hydro--' conjunctiontherewith. and 111 wh c ike re ercarbon oils form heavy polymers in thenature ehce numerals a u d to ndicate like parts in I of tar .or gums.The deposition of these subthe VariOuS w stances in the tubes of a pipestill render ire- Figure 1 is a sectional elevation of a furnace UNITEDSTATES, PATENT OFFICE quent cleaning necessary. Then, too, the highembodying one mode of carrying out my inven- 25 temperatures andpressures involved subject the tlon. tubes of the pipe still to severestresses. This ur 2 1S a sectional p V ew ta en on a produces strainsand permanent distortion. Frene 01 Figure quently, many hydrocarbon oilsbeing processed Fi ure 3 is d view of a h a e u ed n contain sulphurcompounds and/or mercaptans y g out my inv t of a corrosive nature. Theattendant corrosion Fi ure 4 is a sectional, view taken along theresults in the pitting and weakening of thetube e figure wallswith theresult that failures are experienced. u e 5 S a ect ona e eva on 01 afurnace This necessitates the replacing of the tube which embedylflEanother mode carrying out y I as has failed. invention. a v

One object of my invention is to provide a Figure 6 is a sectional viewof a furace embodvnovel construction of a furnace for the pyrolytic ingstill another mode of carrying out my intreatment of hydrocarbon oilswhich will enable vention. f the tubes ofthe furnace to be readilycleaned, Figure 7 is a diagrammatic sectional View.

.4 inspected, removed, and replaced. showing one mode of passing the oflthrough a Another object of my invention is to provide furnace embodyingone manner ofcarrying out a novel and emcient arrangement for pyrolyticmy invention. treatment of hydrocarbon oils whereby they may Moreparticularly referring now to the drawbe heated by radiant andconvection heat in an ing p n a suitable foundation l I build afurefficient manner. nace setting having refractory side walls 2 supOther and further objects of my invention will po ted. by a su tab e seel s uctures. These appear from the following description. n is polyonal in cross section'asjcan readily be In general, my inventioncontemplates the seen by reference to Figure 2 in which it is sheprovision of a furnace setting in the form of a as a hexagon. It is tobe understood, of course,

polygon, as for example pentagon, hexagon, hepthat any suitable numberof sides, from five or 50 tagon, octagon, or the like. Thesetting ispromore, may be used as desired. The greater the vided with reentrantportions at'the intersection number of sides the shorter the lengthofthe of the sides. Short lengths of tubes extend adjatubes which areused in forming the pipe coil of 65 cent the respective sides throughthe reentrant the furnace. The sides are joined by reentrant portions.The tubes are connected byheaders, so portions 4, which are formed bykeyed, rei'rac-y tory blocks 5, which are supported by steel channelcolumns 6, whose .shape can be readily seen by' reference to Figure 2.The short tube sections 1 extend through the reentrant portions adjacentthe side walls of the furnace. Each tube length 1 has a slight pitch andhas its ends extending into a header 8 as can readily be seen byreference to Figure 4. The header 8 consists of a body member havingsomewhat the formof an X, the angle being determined by the type ofpolygon, being used as the setting. If a hexagon is used as shown inFigure 2, the angle between the tube receiving; arms 3 of the header 8would be 120". a

.In axial alignment with each of the tube receiving arms are extensionsl8 provided with slots II in which are positioned the trunnions 12 of ayoke I3, which is provided with a screw threaded bore. Sealing plugs l4are adapted to seat upon suitable seats which are provided with metalgaskets l5. Bolts l6 are adapted to be threaded through the screwthreaded bores of yokes l3 to press plugs l4 against the seats. Thisconstruction can be readily seen by reference to Figures 3 and 4. Theends ofthe'tube 1 are expanded upon suitable seats l1,,- c arrled bytube receiving .por-

tions 9 of the header 8. The tubes 1, when connected by the headers 8,form a spiral coil composed of short lengths of straight pipe. Thelengths of pipe may be'curved if desired. It is essential only thattheybe short so that they may be readily replaced and easily handled. Theoil inlet to the pipe coil formed as just described is tends. Somewherealong one of the lowest passes,

as for example along tube length 22, a pipe connection may be made suchas for example pipe 24 to which a quench oil maybe supplied to controlthe temperature of the oil being processed.

If a cracking operation is going on, over cracking or the temperature ofthe pyrolytic reaction may be controlled by controlling the quench oilthrough pipe 24, provided with a suitable valve.

The oil may be a low boiling oil, if desired. In the form shown inFigure 1, the fuel burners 25 are positioned in the floor of thefurnace, air being supplied through ducts 28 which are provided withsuitable registers 21. If desired, the space 28 may be connected to ablower system (not shown) or a system which supplies preheated air. Thecoil formed by the tube lengths '1 is positioned adjacent the walls ofthe furnace and the oil flowing through this coil will be heatedmainly-by radiant heat. Thefurnace gases will be discharged through anoutlet duct 23, which is positioned with its axis in axial alignmentwith the axis of the setting. This enables a straight line, flow of thefurnace gases without turbulence and makes for a high velocity of flow.

Referringnow to Figure 5, which is a modificationof my invention, thesetting is. a polygonal one as before, with the radiant heat coilarranged as befpre. The duct 29 extends through the setting and isprovided at its upper portion with passages 28- through which thefurnace gases flow I ontheir way to the stack 29'. Positioned withinreplacement may be done from without the-fur- 2,o4s,ss1

ed to be heated mainly by convection heat. The

32 to the coil formed of short lengths in the manner described, in'which it is heated mainly by radiant heat. The furnace is fired adjacentthe bottom of the setting through burners 25, air

being provided through openings 26 supplied with air regulatingregisters 21. It is understood, of course, that the passages 28 may bemade-adjacent the bottom of the' duct 21 and the furnace fired adjacentthe top thereof, if desired. In the form shown in Figure 6, two sets ofburners 25 v are shown having respective air registers 21. The furnaceshown in Figure 6 may be fired either adjacent the top or the bottom or,if desired, both sets of burners may be employed. A tube bank 33 adaptedto be heated mainly by radiant heat is positioned adjacent the ceilingof the setting shown in Figure 6. The tube bank may be used forsuperheating steam or may be connected in series with the coil formed ofshort lengths in the manner described. The duct 29-is positionedadjacent the bottom of the setting and the gases of combustion areadapted to heat tube banks 38 and 34 mainly by convection heat on theirway to the stack 29'.- In the form shown in Figure 6, the oil is chargedto the convection section 38, passes through transfer line 32 to theradiantly heated coil, from which it passes through transfer line 35 tobank 34, which is heated mainly by convection heat from which it passes.through outlet 36..

In the form shown in Figure '7, the oil is charged 35 to convection bank38, from whichit passes to v the radiantly heated coil 33 throughtransfer line 32, then to a convection section 31, then through transferline 38 'to the radiantly heated coil formed of short lengths in themanner described above, then through. transfer line 35 to convectionsection 34, to outlet 36. In the convection section 34, I may introducea quench oil through pipe 24, controlled by valve 38. It is to beunderstood, of course, that this quench oil may be introduced at anysuitable place in the travel oi. the oil, preferably in one of the laterpasses.

It will be seen that I have accomplished the objects of my invention. Ihave provided a furnace for the pyrolytic processing of hydrocarbon oilsin which the oil may be eificiently heated by radiant and convectionheat. The tubes 'of the furnace may be readily removed for replacement,may be cleaned easily and conveniently inspected. It is only necessaryto remove two of the header plugs I 4 to clean or replace any of thetube lengths of the coil. The tube lengths are short and easily handled.The cleaning and nace settingso that it is not necessary t6 permit thefurnace to cool-to such a degree that a man may enter the setting to dothe work. The tube lengths are all of the same length so that a numberof spare tubes may be precut and kept on hand. The advantages of thisarrangement will be manifest.

It'will be understood that certain features and subcombinations are ofutility and may be employed without reference to-other features and 78subcombinations. This is contemplated by and is within the scope of myclaim. It is further obvious that various changes may be made in detailswithin the scope of my claim without departing from the spirit of myinvention. It is therefore, 76

to be understood that my invention is not to be limited to the specificdetails shown and described.

vHaving thus described my invention, what I claim is: a In a furnace forthe pyrolyticprocessing of hydrocarbon oils, a polygonal setting havinglive or more sides, the axis of said setting extending vertically,fuel-burning means within said setting, a coil through which the oil tobe processed is adapted to flow, said coil comprising a plurality ofsubstantially horizontally short lengths of tubing connected in seriesand positioned adjacent the side walls of said setting, a ductpositioned within and extending axially of said setting. a flue, meansproviding communication between said duct and said flue whereby gases ofcombustion may pass from said setting through said duct, heat ex-'change means positioned in said duct and means for connecting said coiland said heat exchange means in series.

CARL 0; MEL-BERG.

